Iggier

I've had my 2011 C-3004M lux for just shy of 7 weeks and it's getting lousy mileage compared to the sticker's quoted 17 city/24 mpg highway rating. So far it's average is 15.8 mpg .

I'm not a high mileage driver, averaging about 100 miles per week. Car has driven about 650 miles since I took ownership (delivered with 4 miles on the odometer), primarily in low speed city/suburb stop and go traffic although occasionally it gets driven on the highway .

Since the car is still in its 1,000 mile break in period, I haven't had it out of "E" - economy mode yet (the 2011 version of what was formerly "C" - comfort mode).

My former C-240 RWD generally exceeded it's 19/24 mpg rating. And that was mostly with a jackrabbit starts.

Can I hope/expect my 2011 C's overall mpg to improve?

Pete7874

Is this according to the computer or is it calculated by you?

city/stop and go traffic will do it to you. Ours gets a a mix of hwy and city traffic and we average about 20-21 mpg during summer... less during winter, so your figures aren't much out of line.

It'll improve when it gets warmer outside, but not by a whole lot.

Iggier

It's per the onboard computer.


Yes...but driven in the same conditions, my previous C - a 2005 RWD model - fared much better on mpg and at least consistent with, if not in excess of the rated mpg. I realize they're two entirely different cars and built years apart, but if anything, I'd have expected efficiency to improve.


I'm a bit dubious here. It's definitely been cold in my area, but the car is generally garage-kept. It's chilly, but not cold, when I start it up.

I'm somewhat suspicious of the increased percentage of ethanol in gasoline as a factor in reducing overall mpg. Despite all the information to the contrary, not all C's are flex-fuel vehicles. Mine is not. No news here, but when I occasionally ran E85 in my prior C, the mpg tanked.

Thanks for sharing your experience.

envyxc350

I get 21 usually with a mix of hwy/city, 13 when im having fun, and 29 when Cruise control it.

I am Jeff

The C-class motors take anywhere between 1500-2500 miles to fully break in. Once they are broken in, they will exceed the sticker mpg.

Pete7874

Really?

32k miles and still waiting for this to happen...

noka

I'm averaging about 23 mpg in 70/30 (Hway/City) driving.

Pete7874

That too, but also, winter gas is formulated differently which further reduces MPG.

jctevere

My sister's 2011 c-class has poor mpg compared to mine, but she only has 1,700 miles. I don't remember around what mileage, but my car had terrible fuel economy and then all of a sudden, got much better. If I had to guess, I would say around 3,000 miles.

Also, expect MPG to be less in winter, see here for more information on why:
http://www.metrompg.com/posts/winter-mpg.htm

On the other hand, I have found that the on-board computer becomes very inaccurate when you leave your car idling (which we do more and more during the winter). What I would suggest you do is also reset your lifetime mpg readings and work off a week of fresh data. The since start figure is not very accurate, and the lifetime figure could be inaccurate now as it is averaging your current mpg with your mpg when you first got the car (which is poor).

Acapulco Bill

That 15.8 MPG just seems too low, perhaps the MB dealer can detect an error code if an injector is not working. My C300's lowest, even when brand new, was 18-19. Got 23 MPG on a 250 mile trip through the mountains (5,000 feet up to 10,000 feet then to sea level) most of this at 115 MPH, loaded with 4 passengers and 300 lbs of stuff in the trunk.
Something must not be right, for how my C300 is driven, it delivers quite acceptable mileage, 20 MPG overall on the computer since new (7k miles), and it is driven pretty much full throttle all the time. And the premium gas in Mexico is like regular in the US. My V12 gets 17 MPG city, driven hard, so please get your MB dealer to sort this out.

C300Sport

Your mileage should improve slightly afer a few thousand miles but I wouldn't expect much more than a couple MPGs improvement if that.
With 100 miles per week average, I assume your typical trip length is pretty short. The "cold" MPGs on any engine is going to be terrible so if you are doing mostly 5 or 10 mile trips, you are probably about right with your figures.
Have you taken a road trip yet?

Iggier

BING BING BING - exactly right. Weekdays, my round trip commute to the office is a whopping 8 miles. The extra 30 or so weekly average is for the other stuff. No road trip yet - it's winter.

Iggier

Thanks. I'll reset the computer. Like yours, a C owner at my office indicated that the mpg improved on his over time. I think C300Sport's post later in this thread pretty much nailed it as well.

victort

my daily work commute is about 6 miles round trip. i warm up my car for about 2 minutes every morning and i avg about 17 mpg doing this. i have about 2600 miles right now and it's around what i was expecting.

Sportstick

Per the cluster displays, my C300 rwd 6 speed has averaged 24.3mpg over 16k miles. My E3504MATIC over 26k miles shows 20.8mpg, with its larger engine in a heavier car. You could wind up between those, unless you continue to mostly drive in low speed stop and go city traffic/short trips. We use only premium fuel and perform a Techron cleaning twice a year (between annual oil changes).